It however does not have issues maintaining the temperature when it’s not actually printing. I can set my hotend to 215 before beggining my print and it’s happy to sit there.
Other problems with it include under extrusion and extruder skipping, as it seems to have troubles pushing the filament out.
What does this sound like it could be? Does it sound like a blockage? Could a blockage cause temperature issues? I have already tried turning off the part cooling fan as I had a similar issue with that a while back but that has no made a difference it seems.
I have the same printer, when I bought it I couldn’t print for shit and what occasionally came out had horrible quality, over/under extrusion, clogged nozzle I was thinking I was the biggest idiot on the planet. After a while it started to occasionally give thermal runaway in the middle of printing. Then one day I decided to disassemble the nozzle because it had clogged and I realized that the thermistor had broken one of the legs but it is making contact because of the screw, I replaced the thermistor and my problems ended. Your description sounds a lot like the problems I had.
Most likely this